Status Display
When iTunes is playing a song selection from a CD, from the iTunes Library, or from a playlist, the Status display (at the top of the iTunes window) shows three lines of information: music identification, music track time, and an audio track bar.118-119

The SnapBack button
The curved arrow on the right side of the Status display is a SnapBack button.The SnapBack button returns you to the song that's currently playing. For example, you play a song from a CD, then you switch to the Library, and then to the iTunes Music Store, and then to a shared playlist. You may not remember where the song that's playing is coming from, but when you click the SnapBack button, iTunes instantly shows the CD's contents and highlights the song that's playing.
